Emergy analysis of Guangzhou National Agricultural Science and Technology Area.

The development of Guangzhou National Agricultural Science and Technology Area (GNASTA) from 2000 to 2004 was analyzed and evaluated using emergy analysis method.Per capita emergy and environmental loading ratio were screened as comprehensive indexes for emergy evaluation of GNASTA by means of principal component analysis method and factor analysis method.Results indicate a rapid and steady increase in total emergy import,total emergy export, emergy demand per area and environmental loading ratio.There is also an undulating increase in average per capita emergy, emergy investment ratio and emergy productivity. Equally, there is an undulating decrease in emergy yield ratio,sustainable development index and emergy consumption for ten-thousand Yuan GDP of GNASTA from 2000 to 2004. The study shows a rapid growing competency of economic and technological sectors of GNASTA.The emergy consumption per cap.and environment loading ratio are selected as comprehensive emergy analysis indexes of agriculture science and technology area by principal component analysis and factor analysis.